Validate URL Parameters on Every Route Change and Redirect-CodePudding

I'm working on an application where most URLs starts with a couple of dynamic parameters. Something like this:

https://projects/:projectId/:subProjectId/<service>/..

However, currently there is no validation of these IDs and I am looking for a proper way to intercept, validate and re-route (if not valid) on every navigation change. Basically I want to parse the URL (using route.paramMap or similar), query the backend DB to check if the IDs exists and re-route to a "Not Found" page if they do not.

I know there are several ways to check for a route change, but I am not sure what the proper approach is for this case. I could subscribe to a routing event or do something like:

<router-outlet (activate)="changeOfRoute()"></router-outlet>

This does not feel correct however as I am not really intercepting the route change and validating/redirecting before the navigation starts. I could also use a route resolver:

resolve: { resolver: IdValidationResolverService}

This is not very practical as I would need to ensure the resolver is used on every route and it's children instead of having something global that applies to every navigation change.

I could use some input on the correct way of handling this.

CodePudding user response：

I think what you need is Guard, for example:

@Injectable({
  providedIn: 'root'
})
export class IdValidatorGuard implements CanActivate {
constructor(private http: HttpClient, private router: Router) {}

 canActivate(
  next: ActivatedRouteSnapshot,
  state: RouterStateSnapshot
 ): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | 
UrlTree {
const id = next.paramMap.get('id');
return this.http.get(`api/validateId/${id}`).pipe(
  map(result => {
    if (result) {
      return true;
    } else {
      this.router.navigate(['/404']);
      return false;
    }
  })
);
}
}